Step 1: Visit and download steam
2.now click on free download...
3.fill in all your details and once you have joined go back to thier home.
Step 2: Now download gmod!
2.now click on COUNTER STRIKE:SOURCE + GARRY'S MOD this will save you loads of time and having to download them seperatley, unless you already have counterstrike or half life or want to play counterstrike or half life...
3.you will now see them both on a kind of "checkout" which will add up the prices of both games(you save money if you buy both games together!) now click purchase and fill out your details (you really have to be a fool if you need a to be instructed how to do that!)
Step 3: Find and install gmod
1.go to youre desktop and you will see a steam shortcut click on this and it then go to the tab that says MY GAMES this will show you the games you have bought! YAY! nearly done :D click on this.
2.here are youre games (note: mine are already installed when you look here you just need to highlight the game you want to install first then click install).
the games take 30mins to 1hour each to install varying on the speed of your pc/laptop/mac and the amount of disk space you have left, i have a laptop with vista and intel dual core-and took me 45mins to install each.
Step 4: Nearly finished!
1.click on garrys mod!